B9

The B9 paper size is an extra-small format that is part of the ISO B series used for highly specialized printing applications and ultra-compact documents. With tiny dimensions of 44 x 62 mm, B9 is even smaller than the standard B8 size. It maintains the distinct height-to-width ratio of 1:√2 (approximately 1:1.4142) that enables consistent scaling across the B system.

With a minuscule surface area of just 0.0027 square meters, B9 provides an extremely space-saving print area optimized for portability. Its microscopic size suits small index cards, mini charts, pocket notes, and specialized prints needing the ultimate compact format. While not an officially defined ISO standard, B9 naturally extends the incremental scaling of the B series for niche contexts requiring an extra-small paper size. It offers a functionally tiny format for portable technical documents and micro-visual information.